LeetCode Solutions/Algorithm I/Day 13 Bit Manipulation/Number of 1 Bits.java
public class Solution {
    // you need to treat n as an unsigned value
    public int hammingWeight(int n) {
        int sum = 0;
        while (n != 0){
            sum += 1;
            n &= (n-1);
        }
        return sum;
    }
}